Fluid controller and fluid meter bypass arrangement

Abstract

A fluid controller ( 17 ) to control flow to a steering cylinder ( 19 ) is modified to include a selector valve assembly ( 41,73 ) having two operating positions. In a first position (“R” in FIG. 1 ), the selector valve ( 73 ) permits fluid flow though the main fluid path ( 53 ) in the normal manner, as would be used when the vehicle is in a “roading” mode. In a second position (“W” in FIG. 1 and in FIG. 3 ), the selector valve ( 73 ) blocks flow through the fluid meter ( 43 ) which normally provides the follow-up movement ( 51 ) to the controller valving ( 31,33 ), and bypasses the fluid meter in a “working” mode. Thus, the normal flow rate can be achieved by merely rotating the steering wheel ( 27 ) an amount which corresponds to the desired deflection of the controller valving ( 31,33 ), without the need for the continuous rotation of the steering wheel, as required during normal steering.

What is claimed is:  
     
       1. A fluid controller operable to control the flow of fluid from a source of pressurized fluid to a fluid pressure operated device; said controller including housing means defining an inlet port for connection to said source of fluid, and first and second control fluid ports for connection to said fluid pressure operated device; controller valve means disposed in said housing means and defining a neutral position, and at least one operating position (FIG. 1) in which said housing means and said controller valve means cooperate to define a main fluid path providing fluid communication from said inlet port to said first control fluid port and including a fluid actuated means for imparting follow-up movement to said controller valve means generally proportional to the volume of fluid flow through said main fluid path when said controller valve means is in said operating position, said fluid actuated means including a rotatable measuring member providing said follow-up movement; characterized by: 
       (a) selector valve means disposed in series flow relationship in said main fluid path, between said fluid inlet port and said fluid actuated means and operable, in a first position (“R” in FIG. 1) to permit normal flow through said main fluid path; and  
       (b) said selector valve means being operable, in a second position (“W” in FIG.  1  and FIGS. 2 and 3) to block fluid flow through said fluid actuated means while bypassing said fluid actuated means, thus permitting flow through said main fluid path while preventing said follow-up movement to said controller valve means.  
     
     
       2. A fluid controller as claimed in claim  1 , characterized by said controller valve means comprises a primary, rotatable valve member and a relatively rotatable, follow-up valve member, said controller valve means defining said main fluid path by rotation of said primary valve member, relative to said follow-up valve member. 
     
     
       3. A fluid controller as claimed in claim  2 , characterized by said housing means cooperating with said controller valve means to define an amplification fluid path including a variable amplification orifice, said variable amplification orifice being variable, between a minimum flow area and a maximum flow area, in response to rotation of said primary valve member relative to said follow-up valve member. 
     
     
       4. A fluid controller as claimed in claim  3 , characterized by said amplification fluid path being in fluid communication with, and receiving fluid from, said main fluid path at a location upstream of said fluid actuated means, and being in fluid communication with, and directing fluid to, said main fluid path at a location downstream of said fluid actuated means. 
     
     
       5. A fluid controller as claimed in claim  1 , characterized by said fluid actuated means comprises an internally-toothed ring member and eccentrically disposed therein, an externally-toothed star member comprising said rotatable measuring member. 
     
     
       6. A fluid controller as claimed in claim  1 , characterized by said selector valve means being operable, in said second position (FIG. 3) to provide direct, relatively unrestricted fluid communication of said main fluid path, upstream of said fluid actuated means with said main fluid path, downstream of said fluid actuated means. 
     
     
       7. A fluid controller as claimed in claim  5 , characterized by said selector valve means being disposed, physically, between said controller valve means and said ring member and said star member of said fluid actuated means. 
     
     
       8. A fluid controller as claimed in claim  1  characterized by said selector valve means comprises a rotatable selector valve including fluid pressure actuated means operable to rotate said selector valve between said first (“R” in FIG. 1) and second (“W” in FIG. 1) positions, in response to a pilot pressure being communicated to a first or a second location in said valve means.